The structure of the gamma subunit of NGF and the binding protein of EGF will be continued. The high degree of similarity observed already will be exploited in completing the sequence analyses by a combination of automatic and manual techniques. Sequence analysis of the C. adamanteus NGF will also be continued to determine to what extent this molecule is different from the cobra and mouse proteins. Studies on the receptors for NGF will be continued. Preparation of plasma membrane receptors from adrenal medulla will be initiated as this represents a much richer source for these moieties. Studies will also be continued on the "down regulation" phenomenon. In particular, metabolic events that might regulate this phase of the NGF response will be manipulated to reveal the intracellular mechanism of the uptake process. Studies in fibroblast growth factor and relaxin will be continued with the view of establishing potential relatedness with NGF. Particular attention will be focused on the carboxyl terminal segment of the beta chain of relaxin which shows a high degree of homology with the corresponding segment of NGF. Both chemical modification and synthetic derivatives will be used in these comparisons.